Full Synthetic to specific node within a pool

We currently are creating specific VIP's (based on port) that points to a specific pool that contains only the server that we would like monitor. We would like to develop a method that we can send traffic to the "production" VIP but introduce some type of host header logic that will send it to a specific server. Does anyone have any suggestions on how to test performance for each server from an outside source without creating specific VIP's?

Thanks,

Joe